Boost 'struggle'??

[pwpanas]

Originally Posted by winnas13

Okay, Supra is back on the road ($700 later)... Now that i've paid more attention, the boost gauge hits about 0.7 bar, So i reckon I'm running the stock boost still. It hasn't played up so far either, nice smooth boost apart from 1 time, in 3rd gear, it boosted nicely, then stopped for 1/2 second then kept going even though my foot stayed flat. It seems the 2 week rest in the garage has fixed some of these problems.. weird.

Another question i have is, From cold start the idle is perfect, sitting at about 1k rpm. When i drive a short distance (4km or so), stop the engine and start it about 15 mins later - The rpm at idle is down at around 400 - 500 and jumps up and down. It might go down to 350 or 400 and almost stall, then jump to 500 - 600 then back down again. Any ideas what might be causing this?

Just curious - what was the $700 for?

The idle issue is likely an IAC problem or a vacuum leak. Is the ecu throwing any codes?

[winnas13]

Originally Posted by pwpanas

Just curious - what was the $700 for?

The idle issue is likely an IAC problem or a vacuum leak. Is the ecu throwing any codes?

$700 for a new wheel bearing and the labour involved. $210 for the bearing, the rest was labour.

Nah the ECU is all clear..

[winnas13]

After doing some reading and searching on google for 'boost leak' I reckon that this is exactly what's wrong with my car. When the boost kicks in it just feels weak and sluggish, maybe overboost?

I'm an absolute noob at this stuff, has anybody posted a how-to?

Extra: Just realised i've never looked at the boost gauge when i floor it. It's all over the place! jumps to 0.5 bar, then down to 0.1.. back up...

Does that scream anything?

[pwpanas]

Originally Posted by winnas13

After doing some reading and searching on google for 'boost leak' I reckon that this is exactly what's wrong with my car. When the boost kicks in it just feels weak and sluggish, maybe overboost?

I'm an absolute noob at this stuff, has anybody posted a how-to?

Extra: Just realised i've never looked at the boost gauge when i floor it. It's all over the place! jumps to 0.5 bar, then down to 0.1.. back up...

Does that scream anything?

You need to pressurize your intake system with an air compressor (up to 15psi should be fine) ... all the way from the air filter/maf back...and listen for leaks. You'll have to rig up an adapter from your intake/maf to the air compressor.

[winnas13]

Originally Posted by pwpanas

You need to pressurize your intake system with an air compressor (up to 15psi should be fine) ... all the way from the air filter/maf back...and listen for leaks. You'll have to rig up an adapter from your intake/maf to the air compressor.

It turned out to be fuel cut!

[pwpanas]

Originally Posted by winnas13

It turned out to be fuel cut!

Awesome - glad you got it figured out, and even more glad that your Mkiv Supra TT is behaving exactly as Toyota built it to.

What I'd be a bit critical of is *anyone* trying to raise boost without doing *all* of the BPU mods. The "BPU" spec was written for a reason - so no one would have to worry about stuff like fuel cut when modding their Mkiv Supra TT! Sigh.

[winnas13]

Originally Posted by pwpanas

Awesome - glad you got it figured out, and even more glad that your Mkiv Supra TT is behaving exactly as Toyota built it to.

What I'd be a bit critical of is *anyone* trying to raise boost without doing *all* of the BPU mods. The "BPU" spec was written for a reason - so no one would have to worry about stuff like fuel cut when modding their Mkiv Supra TT! Sigh.

Yeah... I bought this car from a young girl who obviously did not care for it and had no idea how to. Her idiot boyfriend probably raised the boost and didnt know what to do about the fuel cut!

Thanks for your help